(1) Field of the Invention
The present invention relates generally to an apparatus for dispensing measured amounts of medication to livestock, and in particular to an operator-controlled apparatus for dispensing measured amounts of particulate medication to selected sows among a plurality of sows maintained during gestation in adjacent stalls within a barn.
(2) Description of the Prior Art
In modern pork production, sows are housed in individual stalls within gestation barns. Each barn includes multiple rows of adjacent stalls, each stall normally being about 2xe2x80x2xc3x977xe2x80x2. The front of the stalls in a given row face towards an aisle, with a row of stalls being normally located on either side of the aisle. The sows are normally fed once each day by dispensing pre-measured amounts of feed into a trough in front of the stalls from feed hoppers above the fronts of the stalls. The trough is common to all of the stalls in the row, and can later be flushed and used as a water source by blocking the discharge end of the trough.
During the gestation period, it is also necessary to administer various types of medication, dewormers, feed additives, and the like, referred to herein generally as medication, to the sows. In instances where the medication is to be administered to all of the sows in a given row at the same time, the medication can simply be mixed with the feed, which is then conveyed, such as by an auger, to the individual feed hoppers. However, all of the sows may not be at the same stage of gestation, or may not require a given medication at the same time. Therefore, mixing of the medication into the feed that is provided to all of the sows at the same time, while sometimes practiced, is not a viable solution.
Instead, until the present invention, the normal practice has been for the farm worker to mix the medication into feed batches that are separately hand fed to selected sows, or to walk along the aisle with a container of the medication, such as a bucket, and a measuring scoop, such as a spoon, and manually dispense a scoop of material onto the feed in front of selected sows. This latter procedure is not only time consuming and tiresome, particularly to the back, but is also inaccurate, since the worker may scoop less or more than the accurate amount of medication. In addition, some sows requiring medication may be overlooked. Therefore, there is a need in the industry for a means of quickly and easily dispensing accurately measured amounts of medication to selected sows in a gestation barn.
The present invention addresses this need by providing an apparatus for dispensing measured amounts of medication to selected sows in a gestation barn. Generally, the apparatus is comprised of a medication hopper with a discharge outlet, a measuring valve to remove predetermined volumes of particulate medication from the medication hopper, and a conduit to convey the selected volumes of medication from the valve to the desired discharge point adjacent the sow""s feed area. In addition, a carrying strap may be included if the apparatus is to be carried by the worker. Alternatively, the apparatus may include wheels if the apparatus is to be rolled along an aisleway adjacent the stalls.
The medication hopper preferably tapers inwardly toward its lower end, with a discharge opening being positioned in the lowest end of the hopper. When used, the hopper may be at least partially filled with medication from a bag or other container. Alternatively, an open container of medication may be inverted into the hopper. In another embodiment, the medication hopper may be in the form of a cap having a discharge opening and a threaded rim adapted to receive a container of medication. Other medication hopper configurations will be apparent to one skilled in the art, the only requirement being that a supply of medication is available at the discharge opening for discharge into the measuring valve.
Since precisely measured volumes of medication must be administered, the measuring valve forms a critical component of the apparatus. The valve includes a chamber having a volume corresponding to the volume of the medication to be dispensed, with the chamber being positioned to receive particulate medication from the medication dispenser. The valve further includes a chamber inlet through which medication enters the chamber, and a chamber outlet through which medication is discharged from the chamber. To ensure accuracy, the outlet is closed while the inlet is open for filling of the chamber, with the inlet then being closed prior to opening of the outlet.
In a preferred embodiment, the valve is comprised of a sleeve with a plunger that is snugly slidable within the sleeve. The sleeve, which is positioned horizontally on the apparatus, includes an upper inlet in communication with the hopper discharge port, and an offset lower outlet in communication with the discharge conduit. The plunger, which may be a solid bar, includes a bore that extends vertically transversely through the plunger.
The bore forms the chamber, with the upper opening into the bore forming the chamber inlet and the lower opening into the bore forming the chamber outlet. The sleeve and plunger may be of different cross-sectional profiles, e.g., circular, oval or rectangular. The bore, while conveniently of a circular cross-section, may also be rectangular or oval. Plungers with different volume bores may be used to change the volume of medication dispensed. For example, to simulate dosages currently used, the chamber may have a volume equivalent to one teaspoon, or one or two tablespoons.
The plunger is slidable within the sleeve between a first, or loading, position in which the chamber inlet is aligned with the sleeve inlet, permitting particulate medication to flow into and fill the chamber. In order to dispense the measured volume of material, the plunger is then moved to a second or dispensing position in which the chamber outlet is aligned with the sleeve outlet, allowing the medication to flow from the valve into the discharge conduit.
Movement of the plunger may be effected mechanically or electrically. For example, the valve may include a spring to urge the plunger to the first position, and a cable or cord attached to the plunger. The worker pulls on the cable to pull the valve to the second position. When the cable is released, the valve returns to the first position under the force of the spring. Alternatively, the valve can be attached to a longitudinally aligned solenoid that is in circuit with a battery and a switch, e.g., a pushbutton switch. Activation of the solenoid by pushing the switch to close the circuit moves the plunger to the second position. Other ways to move the plunger between the first and second positions will be apparent to one skilled in the art.
The discharge conduit, which may be a flexible or rigid tube, has a proximal end that is in communication with the valve discharge outlet, and a free distal end that is positionable at the point of discharge, e.g., over the selected sow""s feed. In the wheeled embodiment of the invention, the discharge conduit extends to the side of the apparatus so that the worker can simply push the apparatus along the aisleway with the discharge end of the conduit being positioned over the continuous feed trough. When the discharge conduit is over the feed of a selected sow, the worker discharges the chamber, e.g., by pulling on the cable or by pushing the switch.
To ensure that a measured volume of medication is dispensed to each of the selected sows, the apparatus also preferably includes a counter that is triggered each time the valve is moved to the second or dispensing position. This counter may be activated mechanically by contact of a part of the counter with a moveable part of the valve or cable. Alternatively, the counter can be electrically triggered by placement in the circuit with the solenoid and switch. The particular design of the counter is not critical to the invention, so long as the counter registers one count each time the chamber is emptied.
In the wheeled embodiment of the invention, the dispenser is mounted on a base that has attached wheels and a rearwardly extending handle. Preferably, the base includes a rear axle, with wheels on the outer ends of the axle, and a front wheel. The handle may be telescoping. To mechanically actuate the valve, the cable extends along the handle to a distal end at the top of the handle. The distal end of the cable may be attached to a trigger or lever that is moved rearwardly by the worker to pull the valve plunger to its second position. With the electrically actuated valve, the switch is positioned at the upper end of the handle, while the battery may be positioned in the base of the apparatus.